to build the same end effector.
The files looked good after download with no mesh
doctoring needed, so I went off to the 3D printer. There are
five STL files for this print: the base of the gripper; clamp;
non-driven arm; driven arm; and the linkage. We need one
of each, except the linkage and clamp which need two
The clamp design isn’t really optimized for 3D printing,
so I decided to print it separately so as not to ruin a run of
easy parts if something went wrong. I
turned on the supports and started
After an hour or so, I had two
parts (Figure 3)! The surface finish
wasn’t great and I had to do a bit of
cleanup, but they did print
The rest of the parts were very
straightforward to print. When I woke
up the next morning, I had a set of
parts ready to assemble (Figure 4).
The design was meant to be
assembled with M4 machine screws.
Unfortunately, I had imperial sizes (2-
10), M3, and M5 in the shop. I used
some 6-32 hardware to assemble my
gripper, but wouldn’t necessarily
First, I placed the 9g servo into
the base housing and secured it with
the two screws included for good
measure. This probably wasn’t
necessary, but I’ll
always take any extra
rigidity I can get in
I then put together the linkages and claws with my 6-32
Next, I put the servo arm into its pocket on the driven
arm. Unfortunately, my particular servo had a slightly
different shaped set of arms, so I had to file it a bit, then
insert it into the print. A few minutes later, I had a nice slip
fit and was ready to attach the mechanical parts to the
servo drive spindle.
Before putting the driven arm onto the servo and
The Multi-Rotor Hobbyist
Figure 3: After about an hour, the clamps successfully printed, and just
required some cleanup and removal of support material.
Figure 2: The gripper design by user
yisparyan on Thingiverse looks really nice,
and is a relatively simple afternoon project. If
you don’t have access to a 3D printer, there
are simpler designs that could be cut from
wood, metal, or plastic.
(Image courtesy of yisparyan on Thingiverse.)
Design New Ideas
Cut Real Metal
120VAC - Plug in
Figure 4: All the gripper parts fresh off the 3D
printer and ready to assemble. I’d recommend
ordering the appropriate M4 hardware before
you begin assembly.
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